Railway vehicles operating in northern Europe (e.g. in Scandinavia) are exposed to extreme weather conditions during winter. They have to be designed to withstand substantial amounts of ice and snow. The proper operation of the brake callipers of such railway vehicles in particular must not be jeopardized by the presence of ice or snow.
The freight trains that have traditionally been used in northern Europe have their brake callipers arranged with ample free space around them to ensure their reliable operation. Thanks to the free space, no operation impeding ice or snow can accumulate on the brake callipers.
However, nowadays, passenger trains are more and more common in northern Europe. Passenger trains travel at higher speeds than freight trains, which leads to more snow and ice accumulation on the train components. Also, modern low floor passenger trains such as the Coradia Nordic X62 manufactured by the Applicant have little room around their brake callipers on their bogies.
Due to the compact design of the bogies and the wheel brakes of these modern passenger trains, snow and ice can easily accumulate in the relatively small gaps between the brake calliper components. The accumulated snow and ice can interfere with the movement of the brake calliper components and lead to a failure of the brake.
One way to avoid this ice or snow accumulation is to heat the entire bogie. This solution consumes however a lot of energy. Another option is a regular and preventive de-icing of the bogies in dedicated depots. This is however undesirable since it reduces the running time of the train.